In many technical areas weatherability tests of materials are of considerable importance with respect to economic and safety concerns. Material samples are exposed to environmental conditions which allow for the study of the aging processes of the materials, usually in an accelerated mode.
For organic substances, for example, in particular, elastomer and polymer materials, the ozone-weatherability test is highly important. By exposure to ozone, these materials embrittle very rapidly. On the exposed surfaces, hairline cracks form, which lead to further destruction. Many test methods exist for characterizing the ozone and ultraviolet (UV) light stability of such materials.
For safety relevant lifespan tests, in particular, in the automotive and the aviation sector, extensive corrosion tests are performed. Salt spray chambers allow reproducible, accelerated corrosion tests (salt spray test) according to relevant national and international standards.
Noxious gas tests with specific setups are a known method for determining the effect of corrosive gases on components. Such components may, for example, be components for facilities of the chemical industry or highly stressed components in turbines or process gas compressors.
Systems for weatherability tests, for example, are offered by the company Weiss Umwelttechnik (http:www.wut.com).
German Patent No. 4115586 (Hehl et al.) describes an air conditioning method for a chemical test chamber. The air within an enclosed space can be conditioned by setting its temperature and its humidity.
German Patent No 4236897 (Trubiroha et al.) describes a weathering apparatus for spraying material samples with highly acidic liquids. In addition, the material samples can be exposed to UV light and various gases.
According to these systems, the gases to which the material samples are exposed must be stored. These gases often are corrosive or poisonous and provide a simulation of the effects of environmental contaminants on a material sample. Storage and handling of such gases are problematic. Some substances occurring in typical industrial exposure situations are unstable and must be generated if needed, for example, ozone, radicals, nitrogen oxides, and peroxides to name a few.